1. Field of the Invention
This invention relates to an improvement of intake passage means of an internal combustion engine, by providing a guide plate on the inner peripheral wall of an intake port bored through a cylinder head for communication with a combustion chamber, so that a strong swirl is generated in the intake air-fuel mixture especially at the time of slow running of the engine.
2. Description of the Prior Art
To improve the combustion during light load operation of an internal combustion engine, it has been known to provide a deflector or a guide vane in an intake port of conventional construction as means for generating swirl in intake air-fuel mixture flow. The known means has a shortcoming in that, during heavy load operation of the engine with good combustion, resistance against gas flow therethrough unduly increases, because it controls and rectifiers the entire intake air-fuel mixture in the intake passage, and the increased resistance results in a reduction of the amount of intake air and a considerable reduction of the engine output.
The inventor has proposed to positively revolve a part of intake air-fuel mixture flow during slow running of the engine to cause a strong swirl without increasing resistance against gas flow.
The modified intake passage means, however, has difficulties in that the accurate positioning of the guide plate is not easy and its position tends to be inaccurate, because the guide plate is formed separately from the gasket of an intake manifold. Besides, the airtightness is not perfect.